+int mpc52xx_lpbfifo_start_xfer(struct mpc52xx_lpbfifo_request *req)
+{
+ unsigned long flags;
+
+ if (!lpbfifo.regs)
+ return -ENODEV;
+
+ spin_lock_irqsave(&lpbfifo.lock, flags);
+
+ /*
+ * If the req pointer is already set and a transfer was
+ * started on submit, then this transfer is in progress
+ */
+ if (lpbfifo.req && !lpbfifo.req->defer_xfer_start) {
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+ return -EBUSY;
+ }
+
+ /*
+ * If the req was previously submitted but not
+ * started, start it now
+ */
+ if (lpbfifo.req && lpbfifo.req == req &&
+ lpbfifo.req->defer_xfer_start) {
+ out_8(lpbfifo.regs + LPBFIFO_REG_PACKET_SIZE, 0x01);
+ }
+
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+ return 0;
+}
+EXPORT_SYMBOL(mpc52xx_lpbfifo_start_xfer);
+